Who should do Manual J calc?
My question has to do with industry standard practices. The evaporator coil is leaking on my 9 year old Carrier AC. At 9 years the AC isn't real old but I have had problems with it and decided to replace the system with a 16-18 seer unit. I intend upon getting 3-4 bids for this work.
One of the contractors gave a price for running the Manual J calc.I don't want to pay for this three times. Should I have an independent run the calcs, or can I get one of the bidding contractors to run the numbers and supply the same print out to all?
some contractors will charge a price to do load calcs, but if you choose them they'll deduct it from quote. Some will even do it for free, but sometimes you get what you paid for.
It is a good idea to know up front exactly what size equipment is needed so all bids will be apples to apples.
Thanks. I have a related question. My house is two stories and we have some difficulty balancing the temperature on the second level. The house is well insulated but Orlando can get hot and we use AC year round. Will the Manual J calc help identify any issues with the current ductwork and design?
A manual D is for duct calculations and sizing, that may be helpful for your situation.
a properly done load calculation should help determine this issue.
if you continue to go forward with one system, a cone system will help and can help even the tempuratures between upstairs and down.
apples to apples also includes the type of system, warranties, and efficiencies.
Thanks for the feedback.
In NC, we are required to do Manual J calcs. It takes about half a day to do them. Would you work for half a day for free?
Originally Posted by Ed D
Efficiency applies to work process and equipment
Work Process and type of calc need to be reviewed
Originally Posted by simplyrollin
After you perform 6 calcs and use appropriate templates, whole house calcs should take < 20 minutes for house < 2,000 square feet.
Whole house calcs and room-by-room calcs have distinctly different functions.
A room-by-room calc can be performed in less than an hour with a little practice.
It's Not Rocket Science, But It is SCIENCE
with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE
Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities
I almost asked what a cone system was... only to realize you meant ZONE system. and Yes, I agree.
Originally Posted by beachtech
Originally Posted by lynn comstock
I was scared to ask...thought we had warped into something new.
"Gentlemen. You can't fight in here. This is the War Room!"-Dr. Strangelove (1964)
A good HVAC tech knows how, an educated HVAC tech knows why!
A simple block load for a change out situation should not take more than 30-60 minutes, and we do those for free on any change out we quote. If there is a need to do a room-by-room or a manual D then we do charge for it as it is more labor intensive. We do deduct the cost off the job if it is awarded to us. Minor variations on block loads may occur from one contractor to another so don't be suprised if there is some minor differences. So long as the difference is not more than 5-10% of the total load then I would not worry about it too much.
If one says, say a cooling load of 34,000 and another says 35,500, dont worry about it. If one says 34,000 and another says 42,000 then someone has something wrong and needs to check their math.
It's not rocket-science...
It's electromechanical thermodynamic engineering
I found using a distance meter in addition to a tape measure helps you do it faster.Tape measure for windows and doors.